Open top reservoirs have been used for thousands of years for the storage of water.  This paper covers the history and applications of open-top reservoirs with geosynthetic floating covers.  It covers the design and performance functions of floating covers.  The paper also addresses the notable economics of open-top reservoirs using geosynthetic floating covers for the storage of large quantities of water compared to other common below and above ground structural storage methods used.  It further discusses the proven performance of Chlorosulfonated polyethylene (CSPE) as a long-term material for floating covers.      

Chlorosulfonated polyethylene (CSPE) is a synthetic rubber material noted for its outstanding resistance to chemicals, temperature extremes, and ultraviolet light.  CSPE as a geomembrane was first developed over 40 years ago in the United States as a pond liner material and a roofing membrane.  It has also been used extensively in various regions of the world as a geosynthetic floating cover material for municipal potable water storage and industrial process water containment applications.  CSPE floating covers are designed and used to eliminate evaporation and to prevent contamination and debris from entering the stored water source.

This paper highlights the long history of CSPE floating covers in potable water storage and the materials outstanding UV performance and chemical resistance to chlorine and other chemicals disinfectants used in water treatment.  The paper further profiles three larger floating cover projects located in hot, dry regions for potable water containment where the covers were used in exposed applications for an average of 30 years.  Two of these floating cover projects are in California and the third in the State of South Australia.  In potable water applications, disinfectants including chlorines and chloramines are commonly used for water treatment. These disinfectants can often act as accelerators in the breakdown of the certain geomembrane anti-oxidant packages resulting in premature material aging and failure.  With CSPE, the material goes through a unique polymer cross-linking process where several of the product’s mechanical and endurance properties improve as the material ages.  With over forty years of documented applications, CSPE has proven to be one of the best performing materials for floating covers and geomembranes in long term potable water storage applications.